aspnetcore: Checkbox field is rendered as three(!) input elements with wrong values

Here’s the source CSHTML code:

<input type="checkbox" asp-for="IsConfigured" value="true" disabled="@Model.IsEnabled">

This is what is rendered for the browser, if IsEnabled is false:

<input type="checkbox" value="true" disabled="disabled" checked="checked" data-val="true" data-val-required="The IsConfigured field is required." id="IsConfigured" name="IsConfigured">
<!-- rest of the form -->
<input name="IsConfigured" type="hidden" value="false">
<input name="IsConfigured" type="hidden" value="false">

This is what is rendered for the browser, if IsEnabled is true:

<input type="checkbox" value="true" checked="checked" data-val="true" data-val-required="The IsConfigured field is required." id="IsConfigured" name="IsConfigured">
<!-- rest of the form -->
<input name="IsConfigured" type="hidden" value="false">
<input name="IsConfigured" type="hidden" value="false">

I can’t use that. I need to know whether the checkbox was initially set, no matter whether it was enabled or not. I was about to add a hidden field myself if the checkbox was disabled, but then found this mess that was already added.

Is this a bug or a feature? If it’s a feature, is it correct or broken? And what is it good for?

Additional context

Visual Studio 2017, Windows 10 x64

Add any other context about the problem here. Include the output of dotnet --info

That’s a lot:

.NET Core SDK (gemäß "global.json"):
 Version:   2.2.109
 Commit:    586f23c400

Laufzeitumgebung:
 OS Name:     Windows
 OS Version:  10.0.17134
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\2.2.109\

Host (useful for support):
  Version: 2.2.7
  Commit:  b1e29ae826

.NET Core SDKs installed:
  2.1.402 [C:\Program Files\dotnet\sdk]
  2.1.403 [C:\Program Files\dotnet\sdk]
  2.1.500 [C:\Program Files\dotnet\sdk]
  2.1.502 [C:\Program Files\dotnet\sdk]
  2.1.503 [C:\Program Files\dotnet\sdk]
  2.1.504 [C:\Program Files\dotnet\sdk]
  2.1.505 [C:\Program Files\dotnet\sdk]
  2.1.507 [C:\Program Files\dotnet\sdk]
  2.1.508 [C:\Program Files\dotnet\sdk]
  2.1.509 [C:\Program Files\dotnet\sdk]
  2.2.104 [C:\Program Files\dotnet\sdk]
  2.2.105 [C:\Program Files\dotnet\sdk]
  2.2.109 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

About this issue

  • Original URL
  • State: closed
  • Created 5 years ago
  • Comments: 23 (15 by maintainers)

Most upvoted comments

It’s not for tri-state because there’s no such thing in HTML.

It’s to enable model binding correctly with models that have Boolean values that have a default value of true. In HTML/HTTP, when you post a checkbox value, it either posts checked or it posts nothing. That means that you can set a false Boolean to true, but you can’t set a true Boolean value to false.

Trying to find a link to explain it further, but the thing you posted about how it gets processed looks correct to me.